AND of two minterm expression gives common terms.
$f1\ AND\ f2\equiv f1\cap f2.$
So, $f1\ NAND\ f2\equiv$${(f1\cap f2)'}$
$f1\cap f2=\{0,1,3,5\}\cap\{6,7\}=\phi$
And, we have,
$f=[(f1\cap f2)' \cap (f3)']'=f1 \cap f2 \bigcup f3 = \{1,4,5\}$
But, $f1 \cap f2 = \phi$
$\Rightarrow \phi\ U f3 = \{1,4,5\}$
$ \Rightarrow f3 =\{1,4,5\}$
So, Correct Answer is (A).